Anything that is not obtained through this command is NOT, I repeat, is NOT, a promo.

So um, Spooky Egg is mis-listed as an event item when the page says that it is a promotional item, and it was in fact, a promotional item that was not available via the /promo command. It is listed as a promo in the post that Aikar made for the Halloween promos:

Getting the promos!The Headless Horseman Mask is like last years promo, available to everyone by /promo halloween

Simply log in and type /promo halloween and claim the item!

The Spooky Egg, as well as more of the Headless Horsemen Mask can be purchased at /shop for 15,000 rupees.

The egg is only purchasable from /shop, making it a higher value item after the promo ends.

The Book of Colors could arguably also be a promotional item as it was released in tandem with an acknowledged promotional item and made only available in the shop and not via /promo as well. But this one is actually marked as an event item.. ..I wish I had caught these before I had stepped down as a Contributor..